Adultery is sexual betrayal within marriage, a violation of the seventh commandment. Jesus lists it among the evils that defile from within (Matt 15:19, Mark 7:21). John 8:3 records a woman 'caught in adultery.' The term appears both singular (the act) and plural (the practice or multiple instances). It's a paradigmatic moral violation in biblical ethics, breaking covenant fidelity. The universal translations—'adulterio,' 'adultère,' 'Ehebruch'—show cross-cultural recognition of this offense.